REAPER Daemon

The bridge doesn't open a network port or load an extension into REAPER. It works through files on disk, which means anything that can write a file can drive the DAW. For users, that's a smaller attack surface and fewer moving parts to break. It also means you manage the folders yourself.

REAPER Daemon runs as a defer loop that never exits while REAPER is open. It picks up one command per tick from the inbox, executes it, and writes the result to the outbox. Results arrive as JSON, and every write is atomic, so a reader never catches a half-written file. Slow, but reliable. That trade pays off on long edits.

Every command that changes the project runs inside a REAPER undo block. That's the feature that makes AI control feel safe: Cmd+Z reverts an agent's edit exactly like one you made by hand. Not ideal if you wanted it kept, and that's the point. You can experiment freely and roll back without hunting for a redo.

The loop drops a heartbeat file on every pass. That's how you know it's alive without asking it anything, which matters when the loop and your agent are two separate processes that can drift out of sync. No heartbeat, no confidence.

The daemon ships with no knowledge of any specific synth or amp sim. Your agent calls scan_fx to learn what the project actually contains, then works by name across every effect and every parameter. It adapts to your setup instead of a hardcoded list. No manifest to update.

Commands reach the transport, tempo, cursor, and time selection; tracks (add, delete, rename, volume, pan, mute, solo, arm, color); FX (add, remove, bypass, reorder, parameters, automation envelopes); and the timeline (markers, regions, media items, MIDI insert, audition). Rendering and offline media are covered too. That's most of what a session touches.

Point it at a stem and it walks the take bar by bar. It measures what a drummer listens for: how dense the picking gets, how steady the timing holds, whether notes ring out or die palm muted, where the silence sits, and where the feel changes. Drums then get built against real numbers instead of guesswork.